2002/0404/pc/i8253.c (diff list | history)

2002/0314/sys/src/9/pc/i8253.c:118,136 – 2002/0404/sys/src/9/pc/i8253.c:118,135 (short | long | prev | next)
1997/0327		* prefetch buffer. * */ outb(Tmode, Latch0);
1999/0131		if(havecycleclock)
2001/1130		rdtsc(&a);
2002/0404		outb(Tmode, Latch0);
1997/0327		x = inb(T0cntr); x |= inb(T0cntr)<<8; aamloop(loops); outb(Tmode, Latch0);
1999/0131		if(havecycleclock)
2001/1130		rdtsc(&b);
1997/0327		y = inb(T0cntr); y |= inb(T0cntr)<<8; x -= y;
2002/0404
1997/0327		if(x < 0) x += Freq/HZ;
2002/0314/sys/src/9/pc/i8253.c:137,143 – 2002/0404/sys/src/9/pc/i8253.c:136,141
1997/0327		if(x > Freq/(3*HZ)) break; }                  /* * figure out clock frequency and a loop multiplier for delay().
1999/0131		* n.b. counter goes up by 2*Freq
2002/0314/sys/src/9/pc/i8253.c:144,150 – 2002/0404/sys/src/9/pc/i8253.c:142,147
1997/0327		*/
1999/0131		cpufreq = loops*((aalcycles*2*Freq)/x);
1997/0327		m->loopconst = (cpufreq/1000)/aalcycles; /* AAM+LOOP's for 1 ms */
1999/0131		if(havecycleclock){ /* counter goes up by 2*Freq */